This invention relates generally to ignition systems for internal combustion engines and in particular to means by which an existing combustion engine having a conventional ignition system may be provided with a capacitor discharge ignition system with minimal time and effort. This ignition system is generally of the type disclosed in my copending application for "Ignition System", Ser. No. 460,271, filed Apr. 12, 1974, and the copending application of Richard J. Maier and myself for "Ignition System", Ser. No. 395,908, filed Sept. 10, 1973, now issued as U.S. Pat. No. 3,941,111, both of which are assigned to the assignee of this application. The disclosure of each of those applications is incorporated hereby by reference thereto.
Previously, the complex nature of capacitive discharge ignition systems made them prohibitively expensive for application to smaller internal combustion engines presently utilizing simple magneto ignition systems. With the development of the improved system disclosed in the above referenced copending applications, the number of components, package size, complexity and cost have been reduced sufficiently to allow the incorporation of such systems into these smaller sized engines such as are used in lawnmowers, chain saws, outboard motors, and the like. The ignition systems of the aforementioned applications are generally applicable for incorporation during original equipment manufacture of the associated engines. The present invention provides an inexpensive ignition replacement package whereby existing conventional magneto ignition systems may be easily converted to this improved capacitive discharge system by the owner of the engine subsequent to its initial purchase. The substantial achievement of this invention can be appreciated when the nature of existing engines and their associated ignition systems is considered. In order for a conversion kit to be commercially practical, it must be adaptable for use with a variety of engine configurations. Conventional magneto systems may have a rotor rotating either clockwise or counterclockwise. Also, the leading magnetic pole may be either north or south seeking. Further, the ignition timing of the existing ignition system may not be appropriate due to the differing response characteristics. Additionally, varying existing space limitations must be considered since a conversion would not be commercially practical if significant engine structure modifications were required. The present invention as described herein bridges wide variations in engine and existing ignition systems so as to provide a conversion kit in which a minimum of component structure variations will accommodate a large variety of engine and ignition system configurations without structural modifications.
Additional advantages and features of the present invention will become apparent from the following detailed description taken in conjunction with the attached drawings and appended claims.